Screw holder

ABSTRACT

A screw holder for securing a screw having a longitudinal shank and a central axis, a spindle adjoining the front end of the shank and having a bore therethrough flush with a groove, configured and dimensioned for receiving an elastic component to secure a screw into a steady position while turning the screw in or out.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application No.PCT/CH98/00425, filed Oct. 5, 1998, the disclosure of which is herebyincorporated herein by express reference thereto.

FIELD OF THE INVENTION

This invention is directed to screw holder having a longitudinal shankand a central axis, a spindle located at the front end of the shank,concentric to the central axis, with a bore therethrough and a groovefor receiving an elastic component, preferably, a spring, to secure ascrew, particularly a bone or pedicle screw. The screw holder can beused during minimally invasive surgery.

BACKGROUND OF THE INVENTION

To lessen the damage to soft parts around bone while surgicallyimplanting a screw inside the body, typically to a bone, joint, orvertebra, the procedure should be carried out without uncovering largeareas of the parts to be treated, i.e., smaller incisions and lessinvasive surgery techniques. The use of clamping tongs to insert bone orpedicle screws is no longer suitable when employing minimally invasivesurgery techniques.

European Patent No. 458,449 of Ryder discloses a fastener drive tool forapplying a rotational torque to a threaded fastener for driving thefastener into or out of a workpiece. The drive tool has an elongatedshaft portion with a free end that is engageable with a recess formed inthe fastener. The drive tool has at least one interlobular fastenerretention piece attached between two convex partially-cylindricalsurfaces that engage a corresponding convex partially-cylindricalsurface formed in the fastener recess. The interlobular fastenerretention piece retains the fastener on the drive tool when the drivetool is engaged with the fastener recess and prevents wobbling of thefastener when driven by the drive tool, but requires a significantportion of the surface and, therefore, can weaken the cross-section ofthe shaft, particularly when using smaller screws.

A need exists for a type of screw holder adapted for surgical use.Palliation is a key feature in the design of any surgical tool. A screwholder that might ease the pain typically associated with implantationof a screw into the body, without losing the positive benefits of thesurgery, would be beneficial in the art. The present invention aims atsolving this need in the art by configuring a screw holder to hold abone or pedicle screw while being turned in or out.

SUMMARY OF THE INVENTION

The present invention is directed to a device for securing a screwincluding: a longitudinal shank having a central axis and rear and frontends; a spindle, located at the front end of the longitudinal shankconcentric to the central axis, having front and rear ends, asubstantially polygonal-shaped cross-section with a plurality of roundededges and a plurality of concave side surfaces, a groove substantiallyparallel to the central axis, and a borehole flush with the grooveconcentric to the central axis; and an elastic component having top andbottom ends, with the bottom end inserted into the borehole and the topend inserted into the groove. Preferably, the shank has a first diameterand the spindle has a second diameter less than the first diameter. Thespindle preferably has a hexagonal shape. The elastic component projectstransversely to the central axis across the cross-section whenunstressed. The spindle is received into a screwhead aperture of thescrew, and the screw is secured into position upon stress to the elasticcomponent.

In one embodiment, the rear end of the longitudinal shank is configuredand dimensioned to be received into a motor-driven screwdriver. Inanother embodiment, the rear end of the longitudinal shank is configuredand dimensioned to be received by a screwdriver.

In one embodiment, the groove and the borehole are flush with one of theplurality of rounded edges. In another embodiment, the groove and theborehole are flush with one of the plurality of concave side surfaces.

The elastic component can preferably bend elastically substantiallyperpendicular to the central axis. In one embodiment, the top end of theelastic component is fixed in the groove. In a preferred embodiment, thetop end of the elastic component is bonded, soldered, or clamped intothe groove. In yet another embodiment, the elastic component is a springwire, preferably having a width of 2 mm.

The invention is also directed to a method of securing a screw whileimplanting into a body including: providing a screw having an aperturein a screwhead; providing the device described above; and inserting thespindle into the aperture resulting in stress to the elastic component,wherein upon application of the stress, the elastic component holds thescrew in a steady position.

In one embodiment, the screw is a bone or pedicle screw. In anotherembodiment, the groove and the borehole are flush with one of theplurality of rounded edges. In yet another embodiment, the groove andthe borehole are flush with one of the plurality of concave sidesurfaces.

The elastic component can preferably bend elastically substantiallyperpendicular to the central axis. In one embodiment, the top end of theelastic component is fixed in the groove, preferably bonded, soldered,or clamped into the groove. The elastic component is preferably a springwire.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description which is provided in connection withthe attached drawings, wherein:

FIG. 1 is a sideview according to one embodiment of the invention;

FIG. 2 is a front view according to one embodiment of the invention;

FIG. 3 is a partial section according to the embodiment of the inventionshown in FIG. 2.

FIG. 4 is a front view according to another embodiment of the invention;and

FIG. 5 is a partial section according to the embodiment of the inventionshown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a screw holder for securing a bone orpedicle screw, whether being turned in or out, during surgery. The mainadvantage of the screw holder is that it eliminates the need for thetraditionally used clamping tongs and focuses on minimally invasivesurgery techniques to reduce the damage to the soft parts around bonewhile implanting such a screw.

In one embodiment, shown in FIG. 1, a screw holder 7 includes acylindrical shank 1 having a central axis 5, a rear end 2 and a frontend 21. An affixation means 13 is configured concentrically with thecentral axis 5 at the rear end 2 of the screw holder 7, allowing thescrew holder 7 to be used in a motor-driven screwdriver (not shown). Thescrew holder can also be handled manually. A spindle 4, concentric withthe central axis 5, is present at the front end 21 of the screw holder7. The diameter of the spindle 4 is less than the diameter of thecylindrical shank 1 resulting in a shoulder 3 formed at the front end 21of the cylindrical shank 1.

The spindle 4 has a cross-section 8, shown in FIG. 2, configured so thatthe spindle 4 is insertable into the aperture 14 of a screwhead 16. As aresult, a screw 15 is clamped by the spring 9, shown in FIG. 3, againstthe spindle 4. The spindle 4 is removed from the aperture 14 uponcompletion of the procedure.

FIGS. 2 and 3 show an enlargement view of the spindle 4. The spindleincludes a front end 6 and a rear end 12, with the rear end 12 adjoiningthe shoulder 3 formed at the front end 21 of the cylindrical shank 1.

The screw holder spindle can have various cross-sectional shapes, e.g.,a hexagonal socket. The spindle 4 preferably has a relativelypolygonal-shaped cross-section 8. The polygon corners 10 are rounded andthe sides are concave, resulting in rounded edges 20 parallel to thecentral axis 5. The side surfaces 11 of the spindle 4 are concave andrun parallel to the central axis 5. A groove 17 runs parallel to thecentral axis 5 along one of the concave side surfaces 11. A borehole 18also runs parallel to the central axis 5 flush with the groove 17 and isconfigured and dimensioned for receiving a spring 9, thus allowing for areversible means to secure or clamp the screw while being turned in orout.

The spring 9 may be a leaf spring or another suitable elastic elementcapable of being adapted for the small diameter of the spindle. In apreferred embodiment, the spring may be a simple spring wire less than 2mm, and optionally, the spring may be bent. The spring 9 has a clampedpart 22 to be located inside the borehole 18; the top part 23,optionally bent, of the spring 9 runs in the groove 17 and projectsacross the side surface 11 of the spindle 4 transversely to the centralaxis 5.

The part of the spring 9 providing a means for screw retention 23, inone embodiment being the bent, maybe bonded, soldered, or clamped intothe groove 17 or 19.

The second embodiment of the invention, shown in FIGS. 4 and 5, relatesto the screw holder as described above, with different placement of thegroove and borehole for receiving the spring. Groove 19 and borehole 18are flush along edge 20 of the spindle 4.

It is to be understood that the invention is not to be limited to theexact configuration as illustrated and described herein. For example,the screw holder of the invention may be implemented in various designsusing a spring inserted into a groove. The two embodiments discussed inthe Detailed Description of the Invention, wherein the groove may bepresent in an edge of the cross-sectionally polygonal spindle or it maybe present in a lateral spindle surface running parallel to thelongitudinal axis, are not intended to limit the invention. Accordingly,all expedient modifications readily attainable by one of ordinary skillin the art from the disclosure set forth herein, or by routineexperimentation therefrom, are deemed to be within the spirit and scopeof the invention as defined by the appended claims.

1-12. (canceled)
 13. A method of securing a screw while implanting intoa body comprising: providing a screw having an aperture in a screwhead;providing a device comprising: a longitudinal shank having a centralaxis, a rear end and front end: a spindle, located at the front end ofthe longitudinal shank and concentric to the central axis, having frontand rear ends, a substantially polygonal-shaped cross-section with aplurality of rounded edges and a plurality of concave side surfaces, agroove substantially parallel to the central axis, and a boreholecoextensive with the groove; and a spring wire having top and bottomportions, and a bend positioned between the top and bottom portions,wherein the bottom portion is inserted into the borehole and the topportion is inserted into the grove and has a free end, wherein the topportion projects transversely away from the central axis such that thefree end of the top portion distal to the bend is further away from thecentral axis than any other portion of the top portion when the springwire is unstressed, the spindle being receivable into a screwheadaperture of the screw so that the top portion of the spring wire securesthe screw in position, and wherein the groove and the borehole are flushwith one of the plurality of rounded edges and one of the plurality ofconcave side surfaces: inserting the spindle into the aperture resultingin stress to the spring wire. wherein upon application of the stress,the spring wire holds the screw in a steady position.
 14. The method ofclaim 13, wherein the screw is a bone or pedicle screw.
 15. (canceled)16. The method of claim 13, wherein the groove and the borehole areflush with one of the plurality of concave side surfaces.
 17. The methodof claim 13, wherein the elastic component can bend elasticallysubstantially perpendicular to the central axis.
 18. The method of claim13, wherein the top end of the elastic component is fixed in the groove.19. The method of claim 18, wherein the top end of the elastic componentis bonded, soldered, or clamped into the groove.
 20. (canceled)
 21. Amethod of securing a screw while implanting into a body comprising:providing a screw having an aperture in a screwhead; providing a screwsecuring device comprising: a longitudinal shank having a central axis,a first diameter, a rear end and a front end; a spindle, located at thefront end of the longitudinal shank and concentric to the central axis,having a width, a front end and a rear end, a substantiallypolygonal-shaped cross-section with a plurality of rounded edges and aplurality of concave side surfaces, a groove substantially parallel tothe central axis, and a borehole coextensive with the groove, the widthof the spindle being less than the diameter of the shank; and an elasticcomponent having top and bottom portions, and a bend positioned betweenthe top and bottom portions, wherein the bottom portion is inserted intothe borehole and the top portion is inserted into the groove and has afree end, wherein the top portion projects transversely away from thecentral axis such that the free end of the top portion distal to thebend is further away from the central axis than any other portion of thetop portion when the elastic component is unstressed, the spindle beingreceivable into a screwhead aperture of the screw so that the topportion of the elastic component secures the screw in position; andinserting the spindle into the aperture so that the elastic componentholds the screw in a steady position.